Stock-Based Compensation - Stock Option Activity (Details) - Stock Options	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Stock Options
Beginning, outstanding (in shares) | shares	189,466
Canceled (in shares) | shares	(163,648)
Ending, outstanding (in shares) | shares	25,818
Exercisable (in shares) | shares	25,818
Weighted Average Exercise Price
Beginning, outstanding (in dollars per share) | $ / shares	$ 84.81
Canceled (in dollars per share) | $ / shares	84.73
Ending, outstanding (in dollars per share) | $ / shares	85.32
Exercisable (in dollars per share) | $ / shares	$ 85.32